Fuel Filter Blocking

01 December 2017 #SMMT News

Frequently asked questions

Since winter 2013/14, the issue of diesel fuel filter blocking has affected a relatively small number of cars and vans – around 0.3% of vehicles on the road. Incidents have been reported during cold weather conditions, and mostly in very localised areas of the UK. The problem has not been uniquely experienced by any manufacturer: vehicles of many makes, models and ages have been affected. While a single root cause of the problem remains unclear, vehicle manufacturers, in collaboration with the fuel industry and government, are working hard to put a solution in place.

What is fuel filter blocking?

Fuel filter blocking can occur during cold temperatures when the fuel becomes too viscous to pass through the filter. This can starve the engine of fuel and cause loss of power, resulting in the vehicle either failing to start or going into ‘limp home’ safety mode. Breakdowns can be distressing and inconvenient, but drivers should be reassured that the filter has done what it is designed to do: protect their vehicle’s engine from solid material in the fuel causing costly damage.

What’s being done about it?

SMMT, on behalf of vehicle manufacturers, is collaborating with the fuel industry as part of a government-led British Standards Institute Task Force to establish the root cause of the problem via statistical analysis of breakdown data and testing of affected fuel samples and filters. This has been a highly complex process due to variables in the fuel’s composition over time.

Should I be worried?

The risk of being affected by fuel filter blocking is extremely low – you are around 85 times more likely to call out the breakdown services for a tyre puncture than for a blocked filter. Furthermore, the issue is linked to winter when temperatures fall to 0°C or under. During the summer, the chances of a fuel filter blocking breakdown are minimal, and motorists can be assured that government, the fuel industry and vehicle manufacturers are collaborating to identify the root cause of the issue.

Read the British Standards Institute (BSi) statement

In recent winters a small number of diesel vehicles have experienced problems with fuel filter blocking, causing the engine to either fail to start or go into ‘limp home’ mode.

The British Standards Institution has formed a task force to investigate the issue. The task force includes members of the Downstream Fuel Association, the Petrol Retailers Association, the Society of Motor Manufacturers and Traders, the United Kingdom Petroleum Industry Association, officials from the Department for Transport and representatives from Oil Industry Additive Manufacturers.

Understanding the root cause of the issue has been challenging due to the sporadic and inconsistent nature of the failures. Indeed, it has not been linked to any individual fuel retail sites or fuel suppliers, nor has it just affected individual vehicle makes or models. The
British Standards Institution task force continues to investigate the issue. For further information and to report the issue visit

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